%I A051680
%S A051680 1,27,6291,13589289,266377183929,47123189360124723,
%T A051680 75095231825148137471259,1077370264330489309698453375441,
%U A051680 139124702920688202983704723564457669361
%N A051680 Number of n X n invertible matrices A over GF(3) such that A-I is invertible.
%F A051680 a(n) = 3^binomial(n,2)*b(n), with b(0)=1, b(n)=(3^n-1)*b(n-1)+(-1)^(n). 
               - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 20 2006
%Y A051680 Cf. A002820.
%Y A051680 Sequence in context: A046367 A059795 A123395 this_sequence A013828 A001321 
               A111415
%Y A051680 Adjacent sequences: A051677 A051678 A051679 this_sequence A051681 A051682 
               A051683
%K A051680 nonn,nice
%O A051680 1,2
%A A051680 Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 17 2000